A blast at a Japanese chemical factory killed at least five and left a dozen injured yesterday.
The explosion happened in the early afternoon at the plant in Yokkaichi, when maintenance crews were working on a heat exchanger used in the production of silicon products, a plant spokesman said.
"Five people are dead and 12 have been injured, of whom nine sustained only minor injuries," said a police spokeswoman.
The plant in the south-central city, run by Mitsubishi Materials, makes parts for solar panels and cars, using polymers made from silicon, hydrogen and chlorine.
Television footage showed about a dozen firefighters setting out stretchers for victims at the site, where a pipe appeared to have fallen to the ground and other machinery parts were scattered nearby.
"I heard a boom and saw smoke rising from the plant," a 56-year-old worker at a nearby plant said. "I don't remember there ever being such a serious accident in Yokkaichi before."
A separate police spokeswoman said detailed inspections to determine the cause of the accident had not yet begun because of the danger of secondary explosions, although she added there was no known risk of a toxic chemical leak.
Hiroki Morofuji, an official at the plant, confirmed the explosion involved maintenance workers at the premises.
Mitsubishi Materials, based in Tokyo, makes products including car parts, silicon wafers for memory chips used in consumer electronics, and cement for road and bridge construction.
"Some 170 people were working at the plant," a Tokyo-based spokesman said. "Operations at the plant have been suspended. We still don't know the cause of the explosion."
He confirmed that the Yokkaichi factory was ordered by local officials to shut down for several months in 2010 after an on-site inspection discovered it was generating high-pressure gas without necessary permits.